Bioaccumulation of Heavy Metals and Potential Health Risk through Consumption of Seafoods from Selected Creeks in Rivers State, Nigeria

Excessive oil exploration, pipeline destruction, agricultural activities, and other man-made activities including aerosol sedimentation elevate the levels of heavy metals in the surroundings that leach into the creeks. The seafood bioaccumulates these metals often times within their body system. This work aimed at using seafood samples, Scylla serrata (crab) Clarias gariepinus (catfish), Oreochromis niloticus (tilapia fish), and Physella acuta (snail) as a bioindicator of heavy metal contamination from Ahoada, Omoku, Ndoni, and Choba creeks in Nigeria. The levels of Lead (Pb), Cadmium (Cd), Chromium (Cr), Copper (Cu), Arsenic (As), and Zinc (Zn) were determined in the seafood samples collected from the study creeks during September 2019. Forty-eight (48) samples comprising of S. serrata, C. gariepinus, O. niloticus, and P. acuta were digested and examined for heavy metal concentrations using Flame Atomic Absorption Spectrophotometer. The levels of Pb, Cd, Cr, Cu, As and Zn ranged between 0.310 ± 0.008 to 5.312 ± 0.009 mg/kg; 0.008 ± 0.004 to 1.310 ± 0.010 mg/kg; 2.082 ± 0.012 to 9.013 ± 0.010 mg/kg; 3.014 ± 0.010 to 13.526 ± 0.006 mg/kg; 0.007 ± 0.005 to 0.182 ± 0.005; and 2.015 ± 0.008 to 8.135 ± 0.007 mg/kg respectively. The obtained results were employed in assessing the non-carcinogenic and carcinogenic health risks in humans due to the consumption of the mentioned species. The concentrations of trace elements reported in tissue samples were within the known background levels. However, alarming concentrations were found for Pb, Cd, and Cr that recorded higher values than the safe levels according to the FAO/WHO, and USEPA. The present results revealed that the ingestion of tested species is safe and free from non-carcinogenic risks. However, there is a carcinogenic risk may be emerging due to the steady ingestion of Cr via these aqua forms by the populace.